1. Field of the Invention
The present invention relates generally to catheters inserted into the vascular system for extended periods of time, and more particularly, to an oval IAB catheter for insertion into a blood vessel, and the method for placing such catheter into the blood vessel.
2. Description of the Related Art
Insertion of catheters into the vascular system of humans is a commonly performed procedure. These catheters function as a conduit for inflation of IAB. When a catheter needs to be in place for an extended period of time, it is common to place the catheters from the lower half of the body. Such catheters may have single or multiple lumens, and are typically made from a relatively rigid plastic material with a standard, round cross-section, both to facilitate placement of the catheter into the vessel and to prevent the catheter lumens from collapsing within the vessel. Generally speaking theses catheters are constructed in such a way that the lumen or lumens extending therethrough retain their circular cross-sectional configuration unless an external mechanical force compresses the catheter.
A complication of placing such a catheter is formation of clots on the wall of the catheter located in the vascular system. Blood clots form for several reasons. The vessel causes turbulence and slowing of the blood flow through the vessel, and these factors induce the formation of clots. Generally, the greater the cross-sectional area of the catheter relative to the blood vessel, the greater the induced turbulence and slowing of the blood. In addition, the catheter is a foreign body, and the surface of the catheter in contact with blood is an ideal site for clot formation. Once again, the greater the amount of surface area of the catheter or other foreign body in contact with the blood, the more likely that clots will form.
Such clots can break away and flow in the blood stream to the heart and lungs, causing severe complications. Furthermore, the formation of clots can often cause such vessels to become irreversibly damaged and thrombose, preventing further blood flow through such vessels. This may ultimately cause debilitating swelling of the limb.
Accordingly, it is an object of the present invention to provide a catheter which reduces the likelihood of the formation of clots or reduction in blood flow within the blood vessel into which the catheter is placed while reducing the chances of arterial bleeding at the puncture site of the artery all due to its oval or non-circular shape which has approximately the same perimeter as the balloon attached to the oval catheter.
It is another object of the present invention to provide such a catheter which presents a minimal cross-section obstruction to the normal flow of blood within the blood vessel, yet has a maximum circumference to prevent blood leakage at the point of insertion. However, while it is desirable to have a catheter that has a low profile shape, when such a catheter is inserted behind the balloon bladder attached to the front of the catheter, which bladder is larger than the normally used circular catheter, the bleeding may occur at the site of introduction into the body. This is due to the fact the larger diameter of the wrapped balloon bladder which first enters the insertion site leaves behind a diameter opening larger than the smaller circular catheter following the balloon into the insertion site and thereby leaving a space for blood to flow from said opening. Such a problem is discussed, especially when sheathless insertion is performed, in U.S. Pat. No. 4,897,077. The solution to the blood leakage, in that Patent, was to use a hemostasis sheath, but that doesn't solve the problem of the catheters obstruction of blood flow in the blood vessel.
A still further object of the present invention is to provide a method for conveniently placing such a catheter within the desired blood vessel using commonly available vascular apparatus.
These and other objects of the present invention will become more apparent to those skilled in the art as the description of the present invention proceeds.